Mattresses and cushions for sofas, loveseats, chairs and other upholstery products generally comprise filler materials, batts, and foams, among other layering materials, for achieving a range of comfort, lot and durability. There are a number of advantages to be achieved by the construction of batts from synthetic, staple fiber material for use in mattresses and upholstery cushions. Such fibers are inherently lightweight and therefore easy to ship, store and manipulate during fabrication. These fibers are also generally less moisture absorbent than natural fibers such as cotton, or cellulosic based synthetic fibers such as rayon. Therefore, products made from these fibers can be maintained in a more hygienic condition and dried with much less expenditure of energy. When subjected to open flame, many of these fibers also tend to melt and drip rather than burn. While some of these fibers give off toxic flames, the escape of such fumes has been avoided or minimized by encapsulating the batt in a fire retardant or relatively air impermeable casing. In contrast, fibers such as cotton burn rapidly at high heat and generate dense smoke.
Synthetic fiber batts have been used in mattresses and upholstery cushions since batts maintain their comfort characteristics over time. Traditional batts having desired comfort and height characteristics may generally be too stiff to allow a mattress or futon to be easily rolled for storage or folded into a sofa. As disclosed in U.S. Pat. No. 4,668,562, a batt would be required to create a mattress having the desired comfort characteristics.
Foam materials, in combination with fiber layers, have also been used in the construction of mattresses and upholstery cushions. As disclosed in U.S. Pat. No. 5,317,768, the entire disclosure of which is incorporated herein by reference, an upper surface positioned on top of the general coil structure of a mattress includes a first layer of cover or ticking, a second layer of fiber or filler material, a third layer of a foam having convoluted surface which faces the second layer, and a farther layer of backing material. All four layers are stitched together in a quilt pattern.
Futon furniture in recent years has become a popular alternative to standard upholstered furniture. Futon sofas, loveseats and chairs can be repositioned so that the furniture can be used as a bed. Traditionally, polyurethane foam has been combined with other types of cushioning materials such as cotton batting, latex rubber, and various man-made fiber products in order to impart the desired comfort characteristics to a final product. With time and use, the various types and combinations of materials take on different degrees of set as a result of compression from the weight of a human body. As is often the case with the softer materials, the final product will take more set over time with continued use. The more set the product takes over time, the more comfort, flexibility and height is lost from the product. It is desirable to bend, fold and/or roll up a futon mattress to be used as a sofa or for storage when the futon is not used as a flat sleep surface. Yet, when the futon is used as a sleep surface it must be stiff enough to span slats in a bed frame. Preferably, the material used in making the futon would take on little or no set.
In our prior U.S. patent application Ser. No. 09/363,726 filed Jul. 29, 1999 and Ser. No. 10/124,106 filed Apr. 17, 2002, both entitled “Convoluted Surface Fiber Pad” and since issued as U.S. Pat. Nos. 6,500,292 and 6,40,610, respectively, and hereby incorporated by reference as if reproduced in their entirety, we disclosed a non-woven fiber pad having a convoluted surface and an integral relatively thin but stiff base formed from a non-woven fiber batt. To form the non-woven fiber pad, a non-woven fiber batt is introduced between a pair of counter-rotating drums, at least one of which has a convoluted surface. As the non-woven fiber batt is drawn between the counter-rotating drums, the convolutions upon the surface of at least one roller compresses the surface of the non-woven fiber batt in frictional engagement therewith to a greater or lesser degree depending on the degree of surface relief of the roller convolutions. A heated wire is placed generally parallel to and between the pair of drums so that, as the non-woven fiber batt is drawn between the drums and compressed by the drum convolutions, the heated wire cuts through the non-woven fiber batt to create a cut-pattern generally mirroring the convolutions on the surface of the drum compressing the non-woven fiber batt. The aforementioned cut-pattern results because, whenever a drum convolution compresses the non-woven fiber batt in the vicinity of the heated wire, the wire will pass through the non-woven fiber batt at a point nearer to the batt surface which is in contact with the drum convolution.